Need guidance for creating no dependancies between two installs of Blender
At least on Windows, it is enough to create an empty folder config in Blender\2.70\.

Blender binary path is for example:
...\Blender Foundation\Blender\blender.exe

and the version-specific folder is here:
...\Blender Foundation\Blender\2.70\

Add the config folder like this:
...\Blender Foundation\Blender\2.70\config\

Blender will note the local config folder on startup and prefer it over the user dir. If you save the startup file or user settings, startup.blend and userpref.blend will be created in your local config folder. Scripts located in the user dir won't be picked up.